The five square metre rule nobody mentions

The rule is short. If you lay more than five square metres of impermeable surfacing between the front of your house and the road, and the run-off is not directed to a permeable area within your own boundary, you need planning permission. It came in in October 2008 after a decade of front gardens being paved and urban drainage systems being overwhelmed every time it rained hard.

Almost nobody asks about it. In fifteen years of quoting against other firms we have seen it raised on a customer’s existing quote perhaps a dozen times.

The reason it matters is not that enforcement officers patrol the streets. It is that the rule exists because the problem is real. Water that used to soak into a lawn now runs off a hundred square metres of block paving and into a drain that was sized in 1954, and eventually it comes back up somebody’s driveway.

Designing around it is not difficult and usually costs nothing. Permeable block paving with a permeable sub-base, gravel, resin bound over a permeable build-up, or simply falling the drive toward a planted border with a channel drain all keep you inside permitted development.

What you should not do is lay something impermeable, fall it toward the highway, and hope. That is the version that occasionally ends with a letter, and more often ends with a neighbour whose garage floods when it did not used to.